Circuit breaker



p 1942. E. T. PLATZ 2,297,320

CIRCUIT BREAKER Filed May 9, 1941 3 Sheets-Shqet 1 Sept. 29, 1942. E."r. PLATZ CIRCUIT BREAKER Filed May 9, 1941 3 Sheets-Sheet 2/////////////I/II// TQ/PPED f 2615 INVENTOR KQuM M Sept. 29, .1942. E.r. PLATZ 2,297,320

CIRCUIT BREAKER Filed lay 9, 1941 3 Sheets-Sheet 3 Patented Sept. 29,1942 UNITED STATES PATENT OFFlCE.

' azamzo cmcm'r BREAKER Elwood 'r. Plats, Detroit, Mich, assignor toBulldog Electric Products Company, Detroit, Mich a corporation of WestVirginia Application May 9, 1941, Serial No. 392,603

2 Claims. (01. 200-116) This application relates to circuit breakersand, in one aspect, relates to multipole circuit breakers.

One object of the invention is to provide a multipole circuit breakerall of whose poles will open on the arising of an overload in any pole.In one form of the invention all of the poles open simultaneously: Inanother form the pole in which the overload occurred would open firstand cause the opening of the other poles.

Another object of the invention is to provide a multipole circuitbreaker embodying certain features of circuit breaker construction, suchas a rocker handle, a single spring on each pole for maintaining contactpressure and for pro-, viding a tripping force, trip free operation,etc.

Another object is to provide a circuit breaker wherein a contact armholding element is utilized as an operative connection between thecontact arm and the handle.

A preferred embodiment of the invention is .In these shown in theappending drawings. drawings,

Figures 1 to 3 are section views of the device, along line |-I of Figure5, in three diflerent positions, as indicated.

Figure 4 is a section on line 4-, Figure .5.

Figures 5 and 6 are top and bottom plan views,

. respectively.

Referring to the drawings it will be seen that these show a circuitbreaker casing having a major compartment land a minor compartmentBarriers |2 help to divide the major compartment into three cells, eachcontaining a contact arm or bar H having a movable contact I5 forengaging a stationary contact IS. The barriers |2 thus isolate thediflerent poles, a desirable feature. Each arm has an axle or pin llwhose ends ride in slots l8 formed in the cell walls to permit rockingof the contact arms in paths determined by the guiding portions I!formed on the cell walls.

post at stationary contact IE to the binding post at bracket 21 througha contact bar H, a connector 25, and a warping element 26.

Fixed to the cross shaft 24 and disposed within the cells containing thecontact bars It are arms II to which are connected ends of springs 32 inturn connected to the contact bars l4.

Disposed within the minor compartment H and fixed to cross shaft 24which thus journal them, are a rocker handle 33 and an arm 34, whosefree end is operatively connected to the casing by a suitable overcenteror snap spring arrangement 35.

The operation of the breaker is as follows: Manual switching action isobtainedby movement of the rocker handle, the first part of each strokebeing opposed by the overcenter means 25 and the latter part of eachstroke being aided by such means 35 for typical snap action. Handlemovement will cause rotation of the cross shaft 24 and of the arms 23and 3|. Movement of arms 23 will cause rocking of the contact arms ontheir pivots H by virtue of the operating con nection between the arms23 and contact arms ll established through the latch bars 2|. The

floating of the axles H in slots l8 will permit End lugs 20 o! the armsor bars releasably interlock with slots of latching or holding bars 2|fixed to a transversely extending common trip bar or shaft 22 rotatablymounted or journaled at its ends in arms 23 fixed to a cross shaft 24 inturn journaled in the sides of the casing. A flexible connector 25connects each bar H with a bi-metal warping element 26 anchored to abracket 21 supporting a U shaped magnet 28 surrounding the element 28and cooperating with the metal latch bar 2| to form a magnetic looparound the bi-metal element 26. The circuit for contact pressure for allcontact arms to be equalized while maintained independently by springs32. These springs also provide tripping force to move the arms |lcounterclockwise on their axles free of the handle, when the arms arereleased by the latch bars 2|, incident to overload.

The magnetic loop 282| around each warping element 26 provides for quickopening in the event of a short circuit and accelerates opening of thecircuits on ordinary overloads.

When an overload or short circuit occurs in any pole thelatching bar 2|of that pole is moved counterclockwise to release its arm It so that itwill be tripped by its spring 32. To permit such movement of bars 2|,the common trip shaft 22 is journaled in the arms 23, though normallysprings (not shown) maintain shaft 22 in the position indicated inFigure 1 with latch bars 2i engaging contactarms ll, these springs (notshown) being overcome on overload by the forces which move the latchbars each pole is thus established from the binding 2| counterclockwise,either the warping of the elements 26 or the magnetic forces of themagnetic loops 28--2|.

It will thus be observed that springs 32 have many functions: they aidcircuit opening movement or bars l4 responsive to handle actuation; theycause overload opening movement or bars it without opposing circuitclosing movement; and they also maintain and equalize contact pressure.

For resetting all poles subsequently to an overload release of allpoles, it is merely necessary to move the handle from the position ofFigure 3 to that of Figure 2 so that the lower ends of the latch bars 2!pick up and re-engage the elevated right ends of the contact arms It,the parts assuming the open circuit position of Figure 2- Now havingdescribed the circuit breaker herein disclosed, reference is now made tothe claims winch follow.

1 claim:

1. In a circuit breaker, a movable contact bar having at one point acontact for engaging a stationary contact, holding means releasablyengaging another point on the bar, spring means between the contact andthe holding means for normally biasing the her contact against thestationary contact, when the holding means holds, and for normallybiasing the bar against the holding means so as to be held thereby,means forming a fixed Journal for the bar at a point between the springmeans and the contact'thereof whereby the spring means rocks the bar forcontact separation when the holding means releases the bar, and manualactuation means including a fulcrummed' lever separate and independentof the bar journal means and connected to the holding means for movingit, and for moving the bar when the holding means holds the bar, onthebar Journal point as a pivot, for eil'ecting contact separation, whenthe manual actuation means is moved .in one direction, the manualactuation means also functioning, when moved in the opposite direction,to ret the bar to the stationary contact, the fulcrum of the lever andthe journal of the bar being relatively spaced so that the axes ofrotation of lever and connected at one point of the bar, the aforesaidenemas two points, with the lever fulcrum and the bar journal, defininga parallelogram, whereby the spring means is not stressed during manualactuation movement.

2. In a circuit breaker, a movable contact her having at one point acontact for engaging a stationary contact, holding means releasablyengaging another point on the bar, spring means between the contact andthe holding means for normally biasing the bar contact against thestationary contact, when the holding means means forming a fixed journalfor the bar at a mint between the spring means and the contact thereofwhereby the spring means rocks the I bar for contact separation when theholding all means releases the bar, and manual actuation means includinga fulcrummed lever separate and independent of the bar journal means andconnected to the holding means for moving it, and for moving the barwhen the holding means holds the bar, on the bar journal point as apivot, for efiecting contact separation, when the manual actuation meansis moved in one direction, the manual actuation means also functioning,when moved in the opposite direction, to return the bar to thestationary contact, the fulcrum of the lever and the Journal of the herbeing relatively spaced so that the axes of rotation of lever and barare eccentric, and circuit responsive means for moving the holdingmeans, on overload, away from the bar to release it, the l'ever'and barrotating in parallel planes, said spring means and lever beinginterconnected at one point of the lever, said spring means and herbeing interconnected at one point of the bar, the aforesaid two points,with the lever fulcrum and the bar journal, defining a parallelogram,

whereby the spring means is not stressed during manual actuationmovement, the fulcrum of the lever and the interconnection of the leverand the strip being formed as parallel shafts transverse of the leverand bar and of their planes of rotation, and a handle connected to thelever fulcrum shaft.

